Poet showing how ode to London could start? (4)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

War poet Wilfred Owen. London was christened the Great WEN, a cyst or boil on the face of the earth, by ruralist William Cobbett in the 1820s. So a (rather disparaging) ode to LONDON might start “O WEN!”